The title fight headlined Saturday’s UFC 158 event at Montreal’s Bell Centre and aired on pay-per-view following prelims on FX and Facebook.

St-Pierre’s intensity was evident from the moment he stepped into the cage. Diaz taunted him from the other side of the octagon, and there was no touch of gloves.

As the grudge match kicked off, Diaz walked forward with punches, but St-Pierre answered with kicks to the leg and then scored a takedown just seconds into the opening round. Diaz quickly rolled and turned as he looked for opportunities on the floor, but St-Pierre patiently controlled the positioning as he transitioned from side to side and looked for a chance to take his opponent’s back. Diaz defended well as he turned to create space, but it was complete positional control for St-Pierre throughout the frame.

A frustrated Diaz lunged at St-Pierre well after the bell, but referee Yves Lavigne prevented any contact.

Diaz again fired punches from distance to open the second, and St-Pierre briefly obliged with a few crisp counter punches before driving in for another takedown a little more than 30 seconds into the round. Diaz worked to his knees but found no room for submissions or an escape. A stronger St-Pierre simply out-muscled Diaz while keeping him tight to the mat.

Diaz finally scrambled up with one minute remaining, and the pair traded on the feet until the bell. Diaz failed to gain any momentum, and he was once again pulled away by Lavigne at the bell.

St-Pierre worked a crisp jab to open the third, and Diaz responded with his trademark taunts. However, St-Pierre stuck with the gameplan and scored another takedown. This time Diaz simply crawled to the fence and climbed to his feet, where he again looked to trade. Diaz found some success with a big right to the body and several slapping kicks to the legs. He also defended a handful of takedowns, but none of it fazed St-Pierre, who continued to fire in several crisp jabs.

With one minute left, St-Pierre took a look at the clock and seemed to be tiring as Diaz bloodied up the champ’s nose with a few straight punches. St-Pierre scored another takedown to gain control of the momentum, and Diaz took another swing from his back well after the bell, which prompted a disqualification warning.

As the championship rounds opened, Diaz again found a way to defend the takedown. However, he still found it difficult to outstrike the straight, technical blows of his opponent. Diaz put his hands by his waist to bait St-Pierre, but the champ simply dropped him to the floor and continued his positional domination.

Down four rounds to none, Diaz again looked to strike in the final frame. St-Pierre was unable to score an early takedown, but when Diaz slipped on a high kick, the action again returned to the floor. Diaz scrambled up with less than two minutes remaining, but he couldn’t capitalize on the feet. St-Pierre scored one final takedown in the final minute, and he rained in a few elbows before the final bell.

After an epic pre-fight build up that included much bad blood, Diaz raised St-Pierre’s hand in a nice show of class. St-Pierre returned the favor shortly after, but the winner was evident, and the champion was awarded a clean sweep on the judges’ cards, 50-45 across the board.

“I didn’t want to fight with him in a boxing range because he’s the best boxer in mixed martial arts, and his jiu-jitsu is amazing,” St-Pierre said. “When you fight a guy like this, it’s almost impossible to get ready for them.”

And despite the pre-fight trash-talk that colored the matchup, St-Pierre said he harbored no ill will toward the challenger.

“He did a great job promoting the fight,” St-Pierre said. “Nick Diaz is a good guy. … I never took it personal.”

With the victory, St-Pierre (24-2 MMA, 18-2 UFC) ties UFC Hall of Famer Matt Hughes with the most octagon wins in the promotion’s history with 18. Meanwhile, a dejected Diaz (26-9 MMA, 7-6 UFC), who returned from a 13-month drug suspension following a second failed test due to marijuana, hinted he may be done with MMA.

“I think I’m going to have to just kind of figure out if I want to keep doing this,” Diaz said. “To be honest, I don’t think I’ve really got it anymore.”

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